Build a Mobile App

I am looking for a mobile app to be created (for both iOS and Android) that will need to connect to handle backend queries (authentication, push notifications, database read/writes, etc). You will be tasked with creating the overall framework, that is, the application for both platforms, and the ability to send/receive from a server. Additionally, will be tasked with creating the UI with needed elements. Specific details of this application are still being worked on, but more details will be shared prior to selecting a freelancer.